Form-fill-seal machine

Abstract

A form-fill-seal machine has a tube, a sailor-collar-shaped part, and a vertical sealing mechanism. The sailor-collar-shaped part wraps a sheet-shaped film around the tube so that two edges thereof define overlapping portions. The vertical sealing mechanism ultrasonically seals the overlapping portions of the sheet-shaped film in the vertical direction. The vertical sealing mechanism has an oscillator and a roller. The oscillator generates ultrasonic waves. The roller is disposed downstream of the oscillator along the advancing direction of the film. The roller holds down the film while rotating in the advancing direction of the film after the film has passed the oscillator.

The invention claimed is: 
     
       1. A form-fill-seal machine comprising:
 a cylindrical part; 
 a wrapping part configured to direct a sheet-shaped packaging material to wrap around the cylindrical part so that edges of the sheet-shaped packaging material overlap one another defining overlapping portions; and 
 a conveyor unit for conveying the packaging material along the cylindrical part; 
 a sealing unit for ultrasonically sealing the overlapping portions in a packaging material advancing direction; and 
 a roller adapted to rotate with the packaging material moving in the packaging material advancing direction, the roller being disposed downstream of the sealing unit in a packaging material advancing direction to urge the packaging material against the cylindrical part immediately after the packaging material has passed the sealing unit while the roller rotates, 
 wherein the roller is driven so that a roller speed at which the packaging material is conveyed by the roller is greater than a conveyor speed at which the packaging material is conveyed by the conveyor unit. 
 
     
     
       2. The form-fill-seal machine according to  claim 1 , wherein:
 the roller rotates while holding down both sides of portions sealed by the sealing unit against the cylindrical part. 
 
     
     
       3. The form-fill-seal machine according to  claim 1 , wherein:
 the cylindrical part has a flat surface extending in the advancing direction of the packaging material; and 
 the roller holds down the packaging material against the flat surface after the packaging material has passed the oscillator while the roller rotates in the packaging material advancing direction. 
 
     
     
       4. The form-fill-seal machine according to  claim 1 , wherein:
 an outer peripheral surface of the roller having an indentation such that an area of contact between an ultrasonically sealed part of the packaging material and the roller is reduced, the indentation being formed around the entire periphery of the roller. 
 
     
     
       5. The form-fill-seal machine according to  claim 1 , further comprising:
 an oscillation controller for changing the amplitude of the ultrasonic waves generated by the oscillator according to the speed at which the packaging material is conveyed by the conveyor unit. 
 
     
     
       6. The form-fill-seal machine according to  claim 1 , further comprising:
 a pressure applying unit for pressurizing the oscillator against the packaging material; and 
 a pressure controller for changing the pressure applied by the pressure applying unit according to the speed at which the packaging material is conveyed by the conveyor unit. 
 
     
     
       7. The form-fill-seal machine according to  claim 2 , wherein:
 the cylindrical part has a flat surface extending in the advancing direction of the packaging material; and 
 the roller holds down the packaging material against the flat surface after the packaging material has passed the oscillator while the roller rotates in the packaging material advancing direction. 
 
     
     
       8. The form-fill-seal machine according to  claim 7 , wherein:
 an outer peripheral surface of the roller having an indentation such that an area of contact between an ultrasonically sealed part of the packaging material and the roller is reduced, the indentation being formed around the entire periphery of the roller. 
 
     
     
       9. The form-fill-seal machine according to  claim 1 , wherein the roller is disposed downstream of the oscillator relative to the packaging material advancing direction. 
     
     
       10. The form-fill-seal machine according to  claim 1 , wherein:
 the sealing means further includes an immobile anvil disposed on the cylindrical part so as to face the oscillator. 
 
     
     
       11. The form-fill-seal machine according to  claim 10 , wherein:
 the anvil is attachable and detachable with respect to the cylindrical part. 
 
     
     
       12. The form-fill-seal machine according to  claim 10 , wherein:
 the anvil is disposed on the cylindrical part so as to project outward from an outer surface of the cylindrical pan. 
 
     
     
       13. The form-fill-seal machine according to  claim 10 , wherein the
 sealing means further comprises a roller disposed downstream of the oscillator and the anvil in a packaging material advancing direction, the roller holding down the packaging material after the material has passed the oscillator and the anvil, while the roller rotates with the packaging material moving in the packaging material advancing direction.